Perplexity
AI answer engine with cited sources — a research-first alternative to search.
Directory / Research & Search / NotebookLM
NotebookLM
Upload your sources, then question, summarize, and podcast them.
NotebookLM grounds every answer in documents you upload — PDFs, notes, links — so it only speaks from your sources. The Audio Overview feature turns source sets into a two-host podcast-style discussion.